Module board having embedded chips and components and method of forming the same

ABSTRACT

A module board has embedded chips and components. A substrate has at least one large cavity and at least one small cavity, in which the large cavity passes through the substrate and a passive component is set in the small cavity. A heat-dissipation sheet is set at the bottom of the substrate. A first adhesion layer bonds the bottom of the substrate to the heat-dissipation sheet. At least one IC chip is fixed in the large cavity of the substrate by a second adhesion layer. A dielectric filling layer covers the entire surface of the module board and fills all gaps, in which the dielectric filling layer has a plurality of micro vias to expose partial areas of the IC chip, the passive component and the substrate. At least one wiring pattern layer is formed on the dielectric filling layer and provide electrical connection among the IC chip, the passive component, and the substrate.

This application is a continuation-in-part of application Ser. No.10/431,458 filed on May 8, 2003, now U.S. Pat. No. 6,865,089.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a module board and a method of formingthe same. More particularly, the present invention relates to anintegrated module board, with a structure similar to a cavity-downplastic ball grid array (CD-PBGA) substrate or a substrate havingvarious cavities, in which all kinds of chips and components areembedded or mounted onto the module board.

2. Description of the Related Art

Electrical packaging, including attachment of IC chips, electricalconnections of circuits, sealing, assembly of a circuit board, systemintegration and product packing, integrates IC chips with essentialcomponents to achieve electric communication, circuit-signalcommunication, heat-dissipation path, loading capability and protection.In general, electrical packaging technology is classified into fourfabricating levels. In the first level, electrical connections ofcircuits are completed on a substrate on which IC chips are fixed, andthen the substrate is encapsulated to become a packaging body. In thesecond level, the packaging body is integrated to a circuit board withother electrical components. In the third level, several of the circuitboards are fabricated on a main board to serve as a sub-system board. Inthe fourth level, several of the sub-system boards are combined tocomplete an electrical product.

As the integration grade of IC chips on the substrate increases, the pinnumber of IC input and IC output does also, resulting in a requirementto develop a packaging substrate having a high-density arrangement of ICchips. For example, with a cavity-down plastic ball grid array (CD-PBGA)substrate, the IC chip is fixed in a cavity of the substrate, and isthen electrically connected to bonding fingers on the substrate by anAu-wiring bonding process, and the CD-PBGA substrate is then placed on acircuit board in which the IC chip positioned in the cavity is allowedto attach to the circuit board. Furthermore, a heat-dissipation deviceis installed over the CD-PBGA substrate, and passive components areplaced on the circuit board by an additional assembly process.

This process encounters the following problems. First, the packaging ofIC chips, the assembly of passive components' surface mount technology(SMT) must proceed individually, resulting in a lengthy procedure, lowyield, and high product costs. Second, since the assembly of passivecomponents and the SMT cannot be integrated at the same packaging level,it is impossible to reduce the product to a desired thickness. Third, inorder to achieve heat dissipation, a heat sink/fan and anelectromagnetic interference (EMI) shielding sheet must be furtherprovided on the main board to enhance the electrical performance, alsocausing increased costs. Fourth, since the IC chips, the passivecomponents, and the heat-dissipation device cannot all be integrated onthe same substrate during the same packaging level, the circuit route ofthe product layout is extremely long, interfering with electricalproperties.

Thus, a method of integrating the IC chips, the passive components, andthe heat-dissipation device on a module board during the same packaginglevel to solve the aforementioned problems is called for.

SUMMARY OF THE INVENTION

The present invention provides an integrated module board, withstructure similar to a cavity-down plastic ball grid array (CD-PBGA)substrate or a substrate having various cavities, constituting asubstrate having cavities and a heat-dissipation sheet adhering to eachother. Also, a plurality of passive components (or integrated passivemodule) and IC chips are formed in the cavities of the substrate.Moreover, a multi-layered interconnection process can directly proceedon the module board to provide electrical connection to other circuitboards in a cavity down manner.

A module board having embedded chips and components comprises asubstrate having at least one large cavity and at least one smallcavity, in which the large cavity passes through the substrate and apassive component is set in the small cavity. A heat-dissipation sheetis set at the bottom of the substrate. A first adhesion layer bonds thebottom of the substrate to the heat-dissipation sheet. At least one ICchip is fixed in the large cavity of the substrate by a second adhesionlayer. A dielectric filling layer covers the entire surface of themodule board and fills all gaps, in which the dielectric filling layerhas a plurality of micro vias to expose partial areas of the IC chip,the passive component and the substrate. At least one wiring pattern isformed on the dielectric filling layer and electrically connects to theIC chip, the passive component (or integrated passive module) and thesubstrate.

Accordingly, it is a principal object of the invention to simplify theassembly process.

It is another object of the invention to decrease the process costs.

Yet another object of the invention is to make the electrical test moreconvenient.

It is a further object of the invention to control the thickness of themodule board to decrease the dimensions of the product.

Still another object of the invention is to improve the electricalproperty of the product.

Another object of the invention is to increase the product yield.

These and other objects of the present invention will become readilyapparent upon further review of the following specification anddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 9 are sectional diagrams showing a method of forming themodule board according to the present invention.

FIGS. 10 to 16 are sectional diagrams of the module board according toembodiments of the invention.

Similar reference characters denote corresponding features consistentlythroughout the attached drawings.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a module board, similar to a cavity-downplastic ball grid array (CD-PBGA) substrate or a substrate havingvarious cavities, constituting a substrate having cavities and aheat-dissipation sheet adhering to each other. A plurality of passivecomponents (or integrated passive module) and IC chips are formed in thecavities of the substrate. A multi-layered interconnection process candirectly proceed on the module board to provide electrical connection toother circuit boards in a cavity down manner. In accordance with thenumber of the IC chips and variations in the packaging process, themodule board may serve as a module component, a multi-chip module (MCM)substrate or a main board to be applied to every fabricating level inthe electrical packaging technology.

FIGS. 1 to 9 are sectional diagrams showing a method of forming themodule board according to the present invention.

As shown in FIG. 1, a substrate 22, a first adhesion layer 28 and aheat-dissipation sheet 31 are provided to constitute a module board 30.The first adhesion layer 28 is employed to bond the heat-dissipationsheet 31 to the substrate 22, wherein the first adhesion layer 28 ispreferred to be a conductive paste film. The heat-dissipation sheet 31further provides EMI shielding effect, thus a metal sheet like copper(Cu) is preferred. The substrate 22 comprises a plurality of largecavities 19 for receiving IC chips and small cavities 21 for receivingpassive components (such as resistors, capacitors and sensors).Depending on product designs and process requirements, the profile,size, and number of the large cavity 19 and the small cavity 21 can beappropriately modulated without any limitation. Also, a plurality ofmetal pads 26, alignment marks 27, and passive components 24 arefabricated on the substrate 22. In one preferred case, the passivecomponents 24 are fixed in the small cavities 21, respectively, by anadhesion layer 25. In another preferred case, the passive components 24are embedded into different layers of the substrate 22 using practicaltechnologies. Moreover, the circuit route inside the substrate 22 can bedesigned to various types without detailed description in the figure.

As shown in FIG. 2, using the first adhesion film 28, theheat-dissipation sheet 31 is bonded to the bottom of the substrate 22 toconstitute the module board 30. Also, there remains the large cavities19 to provide predetermined positions of IC chips.

As shown in FIG. 3, at least one IC chip 12 is provided with a pluralityof metal pads 14, electrical-test metal parts 16 and alignment marks 17formed on the surface. Then, using a second adhesion layer 18, thebottom of the IC chip 12 is bonded to the module board 30 within thelarge cavity 19, and the gap between the IC chip 12 and the module board30 serves as a trench 34. Preferably, the thickness of the IC chip 12 isapproximately equal to the height of the substrate 22 to benefitsubsequent processes. The second adhesion film 18 may be conventionaladhesive tape, epoxy-based prepreg tape, thermal conductive film,adhesive film having conductive particles, or metal conductive paste.

Next, a sealing process is performed to protect the IC chip 12 andpassive components 24. As shown in FIG. 4, a dielectric filling layer 36is deposited on the entire surface of the module board 30 to fill thetrench 34 surrounding the IC chip 12 and other gaps surrounding thepassive components 24. Preferably, the dielectric filling layer 36comprises a polymer such as epoxy material and a dielectric material. Inone case, the epoxy material flows into the trench 34 and gaps, and thenthe dielectric material is deposited on the entire surface of the moduleboard 30. In another case, the epoxy material and the dielectric layerare provided on the entire surface of the module board 30 at the sametime, such that the polymer such as epoxy material fills the trench 34and gaps.

Next, a first interconnection process is performed to electricallyconnect the IC chip 12 and passive components 24 to the outside. Asshown in FIG. 5, using laser drilling, plasma etching orphotolithography, a plurality of micro vias 38 are formed in thedielectric filling layer 36 to expose the electrical-test metal parts16, the metal pads 26 and passive components 24, respectively. Then, asshown in FIG. 6, using sputtering, vapor deposition, plating orprinting, a first metal layer 40 is deposited on the entire surface ofthe module board 30 to fill the micro vias 38. Then, as shown in FIG. 7,using photolithography and etching or semi-additive process, the firstmetal layer 40 is patterned as a plurality of first metal wiring layers40A.

Next, a second interconnection process is performed to electricallyconnect the IC chip 12 and passive components 24 to outside. As shown inFIG. 8, in accordance with the aforementioned interconnection process, adielectric layer 42, a plurality of micro vias 43 and a second metallayer are successively formed on the first metal wiring layers 40A.Then, using photolithography and etching or semi-additive process, thesecond metal layer is patterned as a plurality of second metal wiringlayers 44A electrically connected to the first metal wiring layers 40Athrough the micro vias 43.

Depending on the design choice, the electrical connection between thesecond metal wiring layer 44A and other circuit boards in a cavity downmanner may employ direct contact or solder balls or pins. In one case ofusing direct contact, a mask layer is provided to expose predeterminedpositions of the second metal wiring layers 44A to define theelectrically connecting positions. In the other case of using solderballs, as shown in FIG. 9, a plurality of solder balls 48 are fabricatedon the predetermined positions of electrical connection.

As shown in FIG. 9, using printing or photolithography/etching, a masklayer 46 is formed on the entire surface of the module board 30 toexpose predetermined positions of the second metal wiring layers 44A.After coating a solder mask material on the predetermined positions, aplurality of solder balls 48 are placed on the predetermined positions,respectively. Finally, using reflowing, the solder ball 48 is fixed inthe predetermined position. Thus, the solder ball 48 can electricallyconnect to other circuit boards in a cavity down manner. If theintegrated module board is a system or sub-system one, then there willbe no necessity to place solder balls or pins. The module board can useelectrical conduction pads or opto-electronical connectors.

Furthermore, in embodiments of the invention, the substrate 22 can befurther connected to the heat-dissipation sheet 31 through an electricalconduction part 50 in the first adhesion layer 28, as shown in FIG. 10,wherein the heat-dissipation sheet 31 is coupled to ground GND.

Referring to FIG. 11, the small cavity also can pass through thesubstrate, leading the passive component 24 bonded to theheat-dissipation sheet 31 via the first adhesion layer 28. The passivecomponent 24 can be further connected to the heat-dissipation sheet 31through an electrical conduction part 50 in the first adhesion layer 28,wherein the heat-dissipation sheet 31 is coupled to ground GND.

In embodiments of the invention, the module board 30 can furthercomprise additional passive components 24′ set in the large cavity 19,and the additional passive components 24′ can be adjacent to the IC chip12, as shown in FIG. 12. The additional passive components 24′ arebonded on the heat-dissipation sheet 31 by the second adhesion layer 18and connected to the heat-dissipation sheet 31 through an electricalconduction part 50 in the second adhesion layer 18 to couple to groundGND.

In embodiments of the invention, the module board 30 can also comprisean integrated passive component (or module) 52 set in the large cavity19, and the integrated passive component (or module) 52 can be deposedin the small cavity or be adjacent to the IC chip 12, as shown in FIG.13. The integrated passive component (or module) 52 are bonded on theheat-dissipation sheet 31 by the second adhesion layer 18 and connectedto the heat-dissipation sheet 31 through an electrical conduction part50 in the second adhesion layer 18 to couple to ground GND.

In embodiments of the invention, the module board 30 can comprise atleast two Ic chips 12, fixed in the large cavity 19 of the substrate 22by the second adhesion layer 18. The IC chips 12 can be disposed on theheat-dissipation sheet 31, as shown in FIG. 14. Furthermore, the atleast two IC chips can be also fixed in the large cavity and stackedwith each other, as shown in FIG. 15. According to embodiments of theinvention, the stacked IC chips can be electrically connected to eachother, as shown in FIG. 16.

The multi-chip module can include light emitting die oropto-electronical die, and there is cavity or wave guide (or the both)formed over the lighting surface of that to guide the lighttransmission. The wave guide can be any designed pattern built in thesubstrate and connected to the surface or other opto-electronical die.

The module board 30 constitutes the substrate 22 having cavities andheat-dissipation sheet 31 that adhere to each other. Also, the IC chip12 and passive components 24 are embedded in the substrate 22, thus themulti-layered interconnection process can directly proceed on the moduleboard 30 to omit the conventional steps including wiring, assembly ofpassive components and assembly of heat sinks/fans. Moreover, since theIC chip 12 and passive components 24 having different functions areintegrated into the module board 30, the integrated module board 30 isviewed as a system integration package (SIP or SOP) and has advantagesof reducing the size of the circuit board that is subsequently connectedto the module board 30 and decreasing the assembly cost of the passivecomponents 24.

Compared with the prior art, the module board 30 and the method offorming the same have advantages as follows. First, the IC chip 12 isdirectly fixed in the large cavity 19 and the passive components 24 aredirectly fixed in the small cavities 21, thus the modeling process issimplified and the process cost is decreased. Second, theelectrical-test metal parts 16 on the IC chip 12 is electricallyconnected to the solder ball 48 through the first metal wiring layer 40Aand the second metal wiring layer 44A, thus the electrical test is moreconvenient. Third, since the IC chip 12 and passive components 24 areembedded in the module board 30 during the same packaging level, it ispossible to modulate the height of the chip 12 and components 24 tocontrol the thickness of the module board 30, resulting in decreaseddimensions of the product. Fourth, the transmission distance between theIC chip 12 and the passive component 24 becomes closer to improve theelectrical property of the product. Fifth, the conventional stepsincluding wiring, assembly of passive components and assembly of heatsinks/fans are omitted to increase the product yield and decrease theprocess costs. In addition, the module board 30 can be applied to asingle-chip module product, a multi-chip module product, a sub-systemcircuit board, and a system main board.

It is to be understood that the present invention is not limited to theembodiments described above, but encompasses any and all embodimentswithin the scope of the following claims.

1. A module board having embedded chips and components, comprising: asubstrate having at least one large cavity and at least one smallcavity, in which the large cavity passes through the substrate and atleast one passive component is set in the small cavity; aheat-dissipation sheet set at the bottom of the substrate; a firstadhesion layer which bonds the bottom of the substrate to theheat-dissipation sheet; at least one IC chip fixed in the large cavityof the substrate by a second adhesion layer, wherein the IC chipcomprises a plurality of metal pads formed on the surface of the ICchip, wherein a plurality of electrical-test metal parts formed on themetal pads, respectively; a dielectric filling layer covering the entiresurface of the substrate and filling all gaps at the surface of thesubstrate and in all of the cavities, wherein the dielectric fillinglayer has a plurality of micro vias to expose partial areas of the ICchip, the passive component and the substrate; and at least one wiringpattern layer formed on the dielectric filling layer to make the ICchip, the passive component and the substrate electrically connect. 2.The module board having embedded chips and components according to claim1, further comprising an adhesion layer which bonds the passivecomponent in the small cavity.
 3. The module board having embedded chipsand components according to claim 1, further comprising a plurality ofsolder balls, pins, electrical connection pads, or opto-electronicconnectors placed on the wiring pattern layer.
 4. The module boardhaving embedded chips and components according to claim 1, wherein thedielectric filling layer comprises a polymer and a dielectric material.5. The module board having embedded chips and components according toclaim 1, further comprising an electrical conduction part passingthrough the first adhesion layer to connect the substrate with theheat-dissipation sheet, wherein the heat-dissipation sheet is coupled toground.
 6. The module board having embedded chips and componentsaccording to claim 1, wherein the small cavity passes through thesubstrate and the passive component set in the small cavity is connectedto the heat-dissipation sheet through an electrical conduction part inthe first adhesion layer to couple to ground.
 7. The module board havingembedded chips and components according to claim 1, further comprisingat least one passive component, set in the large cavity, adjacent to theIC chip, wherein the passive component set in the large cavity isconnected to the heat-dissipation sheet through an electrical conductionpart in the first adhesion layer to couple to ground.
 8. The moduleboard having embedded chips and components according to claim 1, furthercomprising an integrated passive component, set in the large cavity,adjacent to the IC chip, wherein the integrated passive component set inthe large cavity is connected to the heat-dissipation sheet through anelectrical conduction part in the first adhesion layer to couple toground.
 9. The module board having embedded chips and componentsaccording to claim 1, wherein the at least one IC chip is a plurality ofIC chips fixed in the large cavity and disposed on the heat-dissipationsheet.
 10. The module board having embedded chips and componentsaccording to claim 1, wherein the at least one IC chip is a plurality ofIC chips fixed in the large cavity and stacked each other.
 11. Themodule board having embedded chips and components according to claim 10,wherein the IC chips are electrically connected each other.
 12. A methodof forming a module board having embedded chips and components,comprising steps of: providing a substrate having at least one largecavity and at least one small cavity, in which the large cavity passesthrough the substrate and a passive component is set in the smallcavity; providing a heat-dissipation sheet; providing a first adhesionlayer to bond the bottom of the substrate to the heat-dissipation sheet;providing at least one IC chip, wherein the IC chip comprises aplurality of metal pads formed on the surface of the IC chip, wherein aplurality of electrical-test metal parts formed on the metal pads,respectively; providing a second adhesion layer to bond the bottom ofthe IC chip to the large cavity of the substrate; forming a dielectricfilling layer to cover the entire surface of the substrate and fill allgaps at the surface of the substrate and in all of the cavities; forminga plurality of micro vias in the dielectric filling layer to exposepartial areas of the IC chip, the passive component and the substrate;and forming at least one wiring pattern layer on the dielectric fillinglayer to provide electrical connection among the IC chip, the passivecomponent and the substrate.
 13. The method of forming a module boardhaving embedded chips and components according to claim 12, wherein thepassive component is fixed in the small cavity by an adhesion layer. 14.The method of forming a module board having embedded chips andcomponents according to claim 12, further comprising a plurality ofsolder balls, pins, electrical connection pads, or opto-electronicconnectors placed on the wiring pattern layer.
 15. The method of forminga module board having embedded chips and components according to claim12, wherein the step of forming the dielectric filling layer comprises:proving a polymer to fill all gaps on the surface of the substrate andin all of the cavities; and forming a dielectric material to cover theentire surface of the substrate.
 16. The method of forming a moduleboard having embedded chips and components according to claim 12,wherein at the step of forming the dielectric filling layer, a polymerand a dielectric material are provided at the same time to fill all gapson the surface of the substrate and in all of the cavities and cover theentire surface of the substrate.
 17. The method of forming a moduleboard having embedded chips and components according to claim 12,wherein the first adhesion layer comprises an electrical conduction parttherethrough to connect the substrate with the heat-dissipation sheet,and the heat-dissipation sheet is coupled to ground.
 18. The method offorming a module board having embedded chips and components according toclaim 12, wherein the small cavity passes through the substrate and thepassive component set in the small cavity is connected to theheat-dissipation sheet through an electrical conduction part in thefirst adhesion layer to couple to ground.
 19. The method of forming amodule board having embedded chips and components according to claim 12,further comprising providing at least one passive component set in thelarge cavity, adjacent to the IC chip, wherein the passive component setin the large cavity is connected to the heat-dissipation sheet throughan electrical conduction part in the first adhesion layer to couple toground.
 20. The method of forming a module board having embedded chipsand components according to claim 12, further comprising providing anintegrated passive component set in the large cavity, adjacent to the ICchip, wherein the integrated passive component set in the large cavityis connected to the heat-dissipation sheet through an electricalconduction part in the first adhesion layer to couple to ground.
 21. Themethod of forming a module board having embedded chips and componentsaccording to claim 12, wherein the at least one IC chip is a pluralityof IC chips fixed in the large cavity and disposed on theheat-dissipation sheet.
 22. The method of forming a module board havingembedded chips and components according to claim 12, wherein the atleast one IC chip is a plurality of IC chips fixed in the large cavityand stacked each other.
 23. The method of forming a module board havingembedded chips and components according to claim 22, wherein the ICchips are electrically connected each other.